what do you mean adding javascript to the hamburger quantity and price? do you need to total the values of items selected? you still have not explained what you are trying to do...?

for example if the hamburger is 2.99 and he enters 1 in the quantity field it will tell him it's 2.99 in the sub-total field. If he types 2 in the quantity field it will give him the sup--total of 2 hamburgers in the sub-total field.

mind you, I did not do the whole form, I did hamburger and cheeseburger fields along with subtotal pst, gst, and total fields near the end.
You were very vague on what you wanted so... I didn't quite understand until I was already coding, anyway, this should be a very good start for you.
If you want to move the 'total order' to the button, move the action to your submit button and call calculate_amount() there. hope the helps...

mind you, I did not do the whole form, I did hamburger and cheeseburger fields along with subtotal pst, gst, and total fields near the end.
You were very vague on what you wanted so... I didn't quite understand until I was already coding, anyway, this should be a very good start for you.
If you want to move the 'total order' to the button, move the action to your submit button and call calculate_amount() there. hope the helps...